Collating device, collating method, and program

ABSTRACT

Provided are a collating device, a processing method and a collation program, in which a reference line is extracted from an image and each partial image is moved in a manner that the reference line becomes a predetermined one thereby to correct the image, and in which the corrected image is collated so that an authentication result can be obtained for a short time period without any rotating operation. At first, a reference line extracting unit extracts the center line or the contour line of the image as the reference line. Next, an image correcting unit moves each partial image in parallel thereby to correct the image so that the reference line obtained by the reference line extracting unit becomes a predetermined one. Moreover, an image collating unit collates the image corrected by the image correcting unit and a predetermined image to acquire an authentication result.

TECHNICAL FIELD

The present invention relates to a collating technology.

BACKGROUND ART

The personal identification system is described in Patent Literature 1.This personal identification system includes a light source, an imagingunit, and an image processing unit. A plurality of light-emittingelements, which make the foregoing light source, are arranged accordingto a shape of a finger. The foregoing light-emitting element is anear-infrared high-intensity LED or a laser beam.

The above-mentioned personal identification system operates as follows.

The foregoing light source outputs a weak light for detecting the fingerat any time. The foregoing imaging unit detects whether or not thefinger is exposed to the weak light. When it is detected that the fingerhas been exposed to the weak light, the foregoing light source decideswhich element of the light source is turned on based upon this fingerlocation information. The foregoing light source acquires pixel valueinformation of the image that is being monitored by the foregoingimaging unit, and optimizes the amount of light to be supplied from thelight source. The foregoing imaging unit, after this optimization of theamount of light to be supplied, captures an image of an imaging object(living body). The foregoing image processing unit performs thefollowing image correction (contour extraction/image rotationprocessing) for the image captured by the foregoing imaging unit. Thatis, the foregoing image processing unit firstly performs an edgeemphasizing processing for the captured image, and extracts the contourposition of the finger. The foregoing image processing unit performs therotation processing based upon this extracted contour so that the fingerinclination becomes constant. FIG. 18 shows an example of the contourextraction/rotation processing. FIG. 18( a) is a view illustrating thefinger subjected to the contour extraction, and FIG. 18( b) is a viewillustrating the finger subjected to the rotation correction.

The operation of the authentication is performed through the calculationof correlation to find a similarity between a blood vessel pattern imageof the finger registered in advance and a blood vessel pattern image ofthe finger captured by the imaging unit. An authentication result isobtained by performing a threshold processing for the value obtained bythe correlation calculation.

CITATION LIST Patent Literature

PTL 1: JP-P2002-92616A

SUMMARY OF INVENTION Technical Problem

The technically problematic point of the above-mentioned Patentliterature 1 is that the time for obtaining the authentication result islengthy. That is, the foregoing art necessitates the rotation processingin order to obtain the authentication result. The processing time ofthis rotation processing is long because it demands a large arithmeticamount.

Upon explaining more detailedly, the personal identification system ofthe Patent literature 1 performs the contour extraction for the imageacquired by the image acquiring unit, and performs the rotationprocessing for the image by using the position information of thecontour. Although there are various techniques as this rotationprocessing of the image, any technique demands a large arithmeticamount.

The affine transform is a representative example of the image rotationprocessing. The affine transform, which is a technique obtained bysynthesizing a primary transform and a movement, performs the rotationprocessing of the image. Rotating the image with the affine transformnecessitates obtaining coordinates of the corresponding pixels in thebefore-rotation image and the after-rotation image, and the method ofapplying coordinate transformation matrix exists. Applying thecoordinate transformation matrix per one pixel yields the following.

$\begin{pmatrix}x^{\prime} \\y^{\prime}\end{pmatrix} = {\begin{bmatrix}\alpha & \beta \\\chi & \delta\end{bmatrix}\begin{pmatrix}x \\y\end{pmatrix}}$

This arithmetic operation necessitates performing product computationfour times and sum computation twice, respectively. Applying thecoordinate transformation matrix for the image of which the number ofthe pixels is N necessitates performing the product computation 4×Ntimes and the sum computation 2×N, respectively. Hence, thecomputational complexity becomes very much. That is, the Patentliterature 1 has a problem that the processing time becomes lengthybecause a large computation complexity is required for the rotationcorrectness.

Thus, the problem that is to be resolved by the present invention isresolved by providing an image collating technology capable of obtainingthe authentication result in a short time period.

Solution to Problem

The present invention for solving the above-mentioned problems is acollating device for collating an image that is characterized inincluding a reference line extracting unit for extracting apredetermined reference line in the image, an image correcting unit forcorrecting the image by moving it for each partial image so that thereference line acquired by the foregoing reference line extracting unitbecomes a pre-decided one, and an image collating unit for collating theimage corrected by the foregoing image correcting unit with apredetermined image.

The present invention for solving the above-mentioned problems is acollating method of collating an image that is characterized inincluding a reference line extracting step of extracting a predeterminedreference line in the image, an image correcting step of correcting theimage by moving it for each partial image so that the reference lineacquired by the foregoing reference line extracting step becomes apre-decided one, and a collating step of collating the image correctedby the foregoing image correcting step with a predetermined image.

The present invention for solving the above-mentioned problems is aprogram for causing the collating device to execute a reference lineextracting process of extracting a predetermined reference line in theimage, an image correcting process of correcting the image by moving itfor each partial image so that the reference line acquired by theforegoing reference line extracting process becomes a pre-decided one,and a collating process of collating the image corrected by theforegoing image correcting process with a predetermined image.

The present invention for solving the above-mentioned problems is acorrecting device that is characterized in including a reference lineextracting unit for extracting a predetermined reference line in theimage, and an image correcting unit for correcting the image by movingit for each partial image so that the reference line acquired by theforegoing reference line extracting unit becomes a pre-decided one.

The present invention for solving the above-mentioned problems is acorrecting method that is characterized in including a reference lineextracting step of extracting a predetermined reference line in theimage and an image correcting step of correcting the image by moving itfor each partial image so that the reference line acquired by theforegoing reference line extracting step becomes a pre-decided one.

The present invention for solving the above-mentioned problems is aprogram for causing the correcting device to execute a reference lineextracting process of extracting a predetermined reference line in theimage, and an image correcting process of correcting the image by movingit for each partial image so that the reference line acquired by theforegoing reference line extracting process becomes a pre-decided one.

Advantageous Effect of Invention

The authentication result of the image can be obtained in a short timeperiod. That is, the present invention allows the image to be correctedby moving it for each partial image. And, the image rotation processingthat demands a long time for the processing is eliminated, and theprocessing time required for the image correction is shortened.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a block diagram of the collating device in accordance with afirst exemplary embodiment of the present invention.

FIG. 2 is a schematic drawing of an image acquiring unit in the firstexemplary embodiment of the present invention.

FIG. 3 is a flowchart of the image acquisition in the first exemplaryembodiment of the present invention.

FIG. 4 is a block diagram of a reference line extracting unit in thefirst exemplary embodiment of the present invention.

FIG. 5 is an explanatory view illustrating an example of extracting thecenterline in the first exemplary embodiment of the present invention.

FIG. 6 is an explanatory view illustrating an example of correcting theimage in the first exemplary embodiment of the present invention.

FIG. 7 is an explanatory view illustrating an effect of the imagecorrection upon the curved living body in the first exemplary embodimentof the present invention.

FIG. 8 is a block diagram illustrating an image collating unit in thefirst exemplary embodiment of the present invention.

FIG. 9 is an explanatory view of the image acquiring unit in a secondexemplary embodiment of the present invention.

FIG. 10 is an explanatory view of an example of extracting the referenceline in the second exemplary embodiment of the present invention.

FIG. 11 is a schematic drawing of the image acquiring unit in a thirdexemplary embodiment of the present invention.

FIG. 12 is a block diagram of the reference line extracting unit in afourth exemplary embodiment of the present invention.

FIG. 13 is an explanatory view of an example of correcting thecenterline in the fourth exemplary embodiment of the present invention.

FIG. 14 is an explanatory view of an example of correcting thecenterline in the fourth exemplary embodiment of the present invention.

FIG. 15 is a block diagram of the collating device in accordance withthe present invention.

FIG. 16 is a block diagram of the correcting device in accordance withthe present invention.

FIG. 17 is a block diagram of an information processing system inaccordance with the present invention.

FIG. 18 is an explanatory view of an example of the contourextraction/rotation correction of the prior art.

DESCRIPTION OF EMBODIMENTS

The present invention is a collating device. In particular, the presentinvention is a collating device for collating the image. For example,the present invention is a collating device for collating the image ofthe living body such as a finger, a palm, and a face. This collatingdevice includes a reference line extracting unit for extracting apredetermined reference line in the image. Yet, the collating deviceincludes an image correcting unit (device) for correcting the image bymoving it for each partial image so that the reference line acquired bythe foregoing reference line extracting unit becomes a pre-decided one(for example, a pre-decided line (for example, a straight line), a linehaving a pre-decided position, or a line having a pre-decided shape).Preferably, the collating device includes an image correcting unit(device) for, with the width of a one-pixel portion defined as one line,and the image comprised of at least one line defined as a partial image,correcting the image by translating it for each this partial image sothat the reference line acquired by the foregoing reference lineextracting unit (device) becomes a pre-decided one (for example, apre-decided line (for example, a straight line), a line having apre-decided position, or a line having a pre-decided shape). Inaddition, the collating device includes an image collating unit (device)for collating the image corrected by the foregoing image correcting unit(device) with a predetermined image (for example, the already registeredimage stored in a storing unit (device)). The foregoing reference lineextracting unit is a device for exacting the centerline (or contourline) of the image. The foregoing reference line extracting unitpreferably includes a binarizing unit (device) for extracting one regionor plural regions by binarizing the image, a minute-region removing unit(device) for extracting the region having a maximum area in the regionextracted by the foregoing binarizing unit, and a centerline extractingunit (device) for extracting the centerline from the region extracted bythe foregoing minute-region removing unit. The foregoing reference lineextracting unit preferably includes a centerline correcting unit(device) for correcting the centerline on the basis of the lineequivalent to the maximum length when the centerline extracted by theforegoing centerline extracting unit is comprised of, for example, twolines or more. The foregoing reference line extracting unit preferablyincludes a centerline correcting unit (device) for, when an averagedvalue of the coordinates of the center points within a certain scope,which extends ahead of and behind a certain center point, exceeds athreshold, correcting the centerline extracted by the foregoingcenterline extracting unit by removing the above center point andchanging the coordinate of this removed center point to an average valueof the coordinates of the remaining center points. The foregoingreference line extracting unit can be also configured to adopt not thecenterline but the contour line as the reference line. Additionally,when the contour line is used as the reference line, the so-calledcontour line is at least one part of the contour line. More preferably,it is one part of the contour line. From among, it is the contour linewithin a specific partial region decided for each target of the image.In such a case, the reference line extracting unit includes a binarizingunit (device) for extracting one region or plural regions by binarizingthe image, a minute-region removing unit (device) for extracting theregion having a maximum area in the region extracted by the foregoingbinarizing unit, and a contour line extracting unit (device) forextracting the contour line from the region extracted by the foregoingminute-region removing unit. The foregoing reference line extractingunit preferably includes a contour line correcting unit (device) forcorrecting the contour line on the basis of the line equivalent to themaximum length when the contour line extracted by the foregoing contourline extracting unit is comprised of, for example, two lines or more.The foregoing reference line extracting unit preferably includes acontour line correcting unit (device) for, when an averaged value of thecoordinates of the contour points within a certain scope, which extendsahead of and behind a certain contour point, exceeds a threshold,correcting the contour line extracted by the foregoing contour lineextracting unit by removing the above contour point and changing thecoordinate of this removed contour point to an average value of thecoordinates of the remaining contour points. Various technologies can beadopted for the foregoing image collating unit. For example, the imagecollating unit including a device for performing a Fourier transformline by line, a device for extracting a main component of the featuresby each partial image by performing a linear transform for Fourieramplitude spectra obtained by the foregoing Fourier transform, and adevice for computing a similarity with a dynamic programming matchingoperation by using the main component of the features obtained by theforegoing linear transform can be listed as a preferred one. Herein, theso-called one line is a width of a one-pixel portion. Additionally, asthe preferred device for extracting the main component of the featuresby each partial image, one including a storing device having basismatrixes stored therein that have been obtained by performing a maincomponent analysis for a learning image set, and a device for obtainingthe main component by performing a linear transform for the image byusing the foregoing stored basis matrixes can be listed.

The present invention is a collating method. In particular, the presentinvention is a collating method of collating the image. For example, thepresent invention is a collating method of collating the image of theliving body such as the finger, the palm, and the face. From among, itis a collating method using the foregoing collating device. Theforegoing collating method includes a reference line extracting step ofextracting a predetermined reference line in the image. Further, thecollating method includes an image correcting step of correcting theimage by moving it for each partial image so that the reference lineacquired by the foregoing reference line extracting step becomes apre-decided one (for example, a pre-decided line (for example, astraight line), a line having a pre-decided position, or a line having apre-decided shape). Further, the collating method includes a collatingstep of collating the image corrected by the foregoing image correctingstep with a predetermined image. The foregoing reference line extractingstep is a step of exacting the centerline (or contour line) of theimage. This reference line extracting step preferably includes abinarizing step of extracting one region or plural regions by binarizingthe image, a minute-region removing step of extracting the region havinga maximum area from region extracted by the foregoing binarizing step,and a centerline extracting step of extracting the centerline from theregion extracted by the foregoing minute-region removing step. Thereference line extracting step preferably includes a centerlinecorrecting step of correcting the centerline on the basis of the lineequivalent to the maximum length when the centerline extracted by theforegoing centerline extracting step is comprised of, for example, twolines or more. Or, the foregoing reference line extracting steppreferably includes a step of, when an averaged value of the coordinatesof the center points within a certain scope, which extends ahead of andbehind a certain center point, exceeds a threshold, correcting thecenterline extracted by the foregoing centerline extracting step byremoving the above center point and changing the coordinate of thisremoved center point to an average value of the coordinates of theremaining center points. The foregoing reference line extracting stepcan also adopt not the centerline but the contour line as the referenceline. Additionally, when the contour line is used as the reference line,the so-called contour line is at least one part of the contour line.More preferably, it is one part of the contour line. From among, it isthe contour line within a specific partial region decided for eachtarget of the image. In such a case, the reference line extracting steppreferably includes a binarizing step of extracting one region or pluralregions by binarizing the image, a minute-region removing step ofextracting the region having a maximum area in the region extracted bythe foregoing binarizing step, and a contour line extracting step ofextracting the contour line from the region extracted by the foregoingminute-region removing step. The reference line extracting steppreferably includes a step of correcting the contour line by decidingthe contour line on the basis of the line equivalent to the maximumlength when the contour line extracted by the foregoing contour lineextracting step is comprised of two lines or more. Or, the referenceline extracting step preferably includes a step (a step of correctingthe contour line) of, when an averaged value of the coordinates of thecontour points within a certain scope, which extends ahead of and behinda certain contour point, exceeds a threshold, removing the above contourpoint, and changing the coordinate of this removed contour point to anaverage value of the coordinates of the remaining contour points withregard to the contour line extracted by the foregoing contour lineextracting step. Various technologies can be adopted for theabove-mentioned collating step. For example, the collating stepincluding a step of performing a Fourier transform line by line, a stepof extracting a main component of the features by each foregoing partialimage by performing a linear transform for Fourier amplitude spectraobtained by the foregoing Fourier transform, and a step of computing asimilarity with a dynamic programming matching operation by using themain component of the features obtained by the foregoing lineartransform can be listed as a preferred one. Additionally, as thepreferred step of extracting the main component of the features by eachpartial image, one including a step of obtaining the main component byperforming the linear transform for the image using the basis matrixobtained by performing a main component analysis for a learning imageset can be listed.

The present invention is a program. In particular, the present inventionis a program for causing the foregoing collating device to executevarious processes. Or it is a program for causing the foregoingcollating device to execute the foregoing steps.

While the collating device of the present invention can be alsoconfigured of hardware, it can be also realized with a computer program.

The program of the present invention includes a reference lineextracting process of extracting a predetermined reference line in theimage. Further, the program includes an image correcting process ofcorrecting the image by moving it for each partial image so that thereference line acquired by the foregoing reference line extractingprocess becomes a pre-decided one (for example, a pre-decided line (forexample, a straight line), a line having a pre-decided position, or aline having a pre-decided shape). Further, the program includes acollating process of collating the image corrected by the foregoingimage correcting process with a predetermined image. The foregoingreference line extracting process is a process of exacting thecenterline (or contour line) of the image. This reference lineextracting process preferably includes a binarizing process ofextracting one region or plural regions by binarizing the image, aminute-region removing process of extracting the region having a maximumarea from region extracted by the foregoing binarizing process, and acenterline extracting process of extracting the centerline from theregion extracted by the foregoing minute-region removing process. Theforegoing reference line extracting process preferably includes acenterline correcting process of correcting the centerline on the basisof the line equivalent to the maximum length when the centerlineextracted by the foregoing centerline extracting process is comprisedof, for example, two lines or more. Or, the foregoing reference lineextracting process preferably includes a process of, when an averagedvalue of the coordinates of the center points within a certain scope,which extends ahead of and behind a certain center point, exceeds athreshold, correcting the centerline extracted by the foregoingcenterline extracting process by removing the above center point andchanging the coordinate of this removed center point to an average valueof the coordinates of the remaining center points. Or, the foregoingreference line extracting process can also adopt not the centerline butthe contour line as the reference line. Additionally, when the contourline is used as the reference line, the so-called contour line is atleast one part of the contour line. More preferably, it is one part ofthe contour line. From among, it is the contour line within a specificpartial region decided for each target of the image. In such a case, thereference line extracting process preferably includes a binarizingprocess of extracting one region or plural regions by binarizing theimage, a minute-region removing process of extracting the region havinga maximum area in the region extracted by the foregoing binarizingprocess, and a contour line extracting process of extracting the contourline from the region extracted by the foregoing minute-region removingprocess. The foregoing reference line extracting process preferablyincludes a process of correcting the contour line by deciding thecontour line on the basis of the line equivalent to the maximum lengthwhen the contour line extracted by the foregoing contour line extractingprocess is comprised of two lines or more. Or, the reference lineextracting process preferably includes a process of, when an averagedvalue of the coordinates of the contour points within a certain scope,which extends ahead of and behind a certain contour point, exceeds athreshold, correcting the contour line extracted by the foregoingcontour line extraction process by removing the above contour point andchanging the coordinate of this removed contour point to an averagevalue of the coordinates of the remaining contour points. Varioustechnologies can be adopted for the above-mentioned collating process.For example, the collating process including a process of performing aFourier transform line by line, a process of extracting a main componentof the features by each foregoing partial image by performing a lineartransform for Fourier amplitude spectra obtained by the foregoingFourier transform, and a process of computing a similarity with adynamic programming matching operation by using the main component ofthe features obtained by the foregoing linear transform can be listed asa preferred one. Additionally, as the process of extracting the maincomponent of the features by each partial image, one including a processof obtaining the main component by performing the linear transform forthe image using the basis matrix obtained by performing a main componentanalysis for a learning image set can be preferably listed.

In the present invention, the following coordinate transform isperformed at the moment of obtaining the coordinates of thecorresponding pixels that correspond to the before-correction andafter-correction images.

y=y′+ε

The coordinate transform of the pixel in the present invention isone-directionally performed. The number of the coordinate values of thepixel is two because the image is two-dimensional, but the number of thecoordinates associated with the coordinate transform is one (1). Thus,the processing required for the coordinate transform is finished withthe one-time sum computation. When the coordinate transform is appliedfor the image of which the number of the pixels is N, the processing isfinished with the N-time sum computation. On the other hand, when thecoordinate transform in the image rotation processing is applied for theimage of which the number of the pixels is N, it is necessary to performthe product computation 4×N times, and the sum computation 2×N times.Thus, the present invention allows the computational complexity requiredfor the image correction to be drastically reduced. Hence, a reductionin the processing time can be realized. Namely, performing the imagecorrection by each partial image as mentioned above makes it possible toomit the rotation processing of the image. And, the processing timerequired for correcting the image is shortened.

Hereinafter, the present invention will be explained yet specifically.

FIG. 1 is a block diagram of the collating device of the first exemplaryembodiment of the present invention.

The collating device of the present invention includes an imageacquiring unit 101, a reference line extracting unit 102, an imagecorrecting unit 103, and an image collating unit 104. The imageacquiring unit 101 is a device for acquiring the image, being an imagingtarget. The reference line extracting unit 102 is a device forextracting the reference line from the image acquired by the imageacquiring unit 101. The image correcting unit 103 is a device forperform the position correction of the image based upon the referenceline extracted by the reference line extracting unit 102. The imagecollating unit 104 is a device for collating the image corrected by theimage correcting unit 103 with a predetermined image (already registeredimage).

The image acquiring unit 101 includes, for example, near-infrared LEDs201, an infrared transparent filter 202, an imaging device 203 (see FIG.2). Additionally, in FIG. 2, the portion (finger-shaped portion)depicted in the utmost top is a imaging target.

The near-infrared LED 201 is used as a light source for illumination atthe moment of capturing the image of the imaging target. Thenear-infrared LEDs 201 are arranged in a side identical to that of theimaging device 203 with the imaging target taken as a reference.Arranging the near-infrared LEDs 201 in such a manner allows lightreflected mainly at a skin surface to be observed. And, the image of thesurface pattern of the imaging target is captured. Such an imagingmethod (the method of arranging the light source in a side identical tothat of the imaging device 203 with the imaging target taken as areference, and observing the reflected light) is called a reflectedlight sensing.

In the present invention, as the imaging target, in particular, theportions such as the finger, the palm, and the face can be listed.Additionally, from now on, the personal authentication in the case ofusing the finger as the imaging target will be explained basically.However, the situation is similar with a case of applying for the palmand the face.

A fingerprint exists on the surface of the finger. The fingerprint has aridge (a projected portion on the skin surface) and a recess (hollowedportion). In the ridge portion of the finger, the thickness of the skinsurface is thick, and blood flowing into the blood vessel is hardlyobserved. And, in the surface of the ridge portion of the finger, thecaptured image is bright because the amount of diffused reflection andspecular reflection becomes much. In the recess portion of the finger,the thickness of the skin surface is thin, and the amount of lightpermeating into dermis under the skin surface, in which the blood vesselexists, is much. And, in the recess portion of the finger, the capturedimage is dark because absorption of light is much, diffused reflectionis much and specular reflection is few. From such a background, thenear-infrared LEDs 201 are arranged so that the light amount of thespecular reflection becomes much in order to suppress unevenness ofillumination caused by a localized shape of the finger.

The infrared transparent filter 202 is an infrared transparent filter(IR filter) that passes, for example, near-infrared ray with awavelength of 700 to 900 nm. Using the IR filter makes it difficult topass light having a wavelength shorter than the limited wavelength thatis decided based upon a filter feature. As a result, an influence of theturbulence light such as room illumination and sunshine can be reduced.

The infrared transparent filter 202 is installed in a lens unit of theimaging device 203 (see FIG. 2). Additionally, the infrared transparentfilter 202 may be arranged between the near-infrared LEDs 201 and theimaging device 203, and an imaging target (finger) instead of installingthe infrared transparent filter 202 in the lens unit of the imagingdevice 203, partly because of protecting the near-infrared LEDs 201 andthe imaging device 203.

The imaging device 203 includes a two-dimensional imaging element (forexample, a CCD sensor or a CMOS sensor) and a lens. Preferably, thetwo-dimensional imaging element is an element having resolution matchedto the living body of which image is captured. When image of the portionranging from the middle phalanx of the finger to fingertip is capturedat approximate 500 dpi, for example, the element of 1.3 million pixelshaving 1280×1024 pixels is used.

The followings proceed so as to acquire the image of the imaging targetby using the above-mentioned image acquiring unit (device) 101.

At first, the near-infrared LEDs 201 are illuminated, and the image ofthe imaging target is captured by the imaging device 203.

It is determined according to a flow shown in FIG. 3 whether the imageis acquired.

In a step 301 (acquiring the image), the image is acquired by theimaging device.

In a step 302 (calculating a difference with the previous image), atotal sum of the difference of the image between last-time image andthis-time image for the frames is calculated.

In a step 303 (the finger arranged?), a value of a status flag forkeeping information as to whether or not the finger has been arranged isdetermined. With the status in which the finger has not been arranged,the operation proceeds to a step 304 (the total sum is larger than athreshold?). And, it is determined whether or not the calculated totalsum of the difference between the images is larger than a threshold.When it is larger than a threshold, it is determined that the imagingtarget has been placed. That is, in a step 305 (it is determined thatthe finger has been placed), the status flag is updated. Thereafter, theoperation returns to the step 301, the image is re-acquired, and a totalsum of the difference with the previous image is calculated.

On the other hand, with the status in which the finger has beenarranged, it is determined in a step 306 (the total sum is smaller thana threshold?) whether or not the total sum of the difference is largerthan a threshold. When it is smaller than a threshold, the operationproceeds to a step 307 (outputting the acquired image) by determiningthat no movement of the finger exists. And, the image acquired at thistime is outputted. When it is larger than a threshold, the operationreturns to the step 301, and the image is re-acquired.

The reference line extracting unit 102 extracts the reference line,being a reference of the image correction, from image of the imagingtarget acquired by the image acquiring unit 101. The extracted referenceline is founded upon the features of the living body, being a target.For example, with the case that the living body, being a target, is thefinger, a specific line that is decided based upon the centerline (or,the contour line or both of the centerline and the contour line) of thefinger. With the case that the living body is the face, for example, thebridge of the nose passing through the middle of the eyebrows and thenose tip is defined as the reference line.

Hereinafter, the case that the centerline is extracted as the referenceline of the finger will be explained. Additionally, the centerline iscentrally positioned from a boundary (contour).

The reference line extracting unit 102 of this exemplary embodimentincludes a binarizing unit 401, a minute-region removing unit 402, and acenterline extracting unit 403 (see FIG. 4). The binarizing unit 401 isa device for performing a binarization processing for the image of theimaging target acquired by the image acquiring unit 101. Theminute-region removing unit 402 is a device for removing minute regionsfrom the image binarized by the binarizing unit 401, and extracting theregion (maximum region) of the finger. The centerline extracting unit403 is a device for extracting the centerline of the above region fromthe region (maximum region) of the finger extracted by the minute-regionremoving unit 402.

Next, an operation for extracting the reference line from the imageacquired by the image acquiring unit 101 will be explained.

The binarizing unit 401 performs a threshold processing for the imageacquired by the image acquiring unit 101. This allows the image to bebinarized. The image acquired by the image acquiring unit 101 is animage captured by the imaging device 203 as a result of thenear-infrared ray emitted from the near-infrared LEDs 201 beingreflected at the finger. Thus, in the acquired image, the region inwhich the finger exists is bright (the pixel value is large). On theother hand, in the acquired image, the region in which no finger existsis dark because the near-infrared ray is not reflected and yet aninfluence of the turbulence light such as room illumination and sunshineis reduced by the infrared transparent filter 202. In such a manner, inthe acquired image, the region of the finger becomes a region having alarge pixel value and the region in which no finger exists becomes aregion having a small pixel value. The binarizing unit 401, which aimsfor extracting the region equivalent to the finger, binarizes the imagewith the decided threshold defined as a reference so that the region ofthe finger and the background are separated excellently.

The minute-region removing unit 402 removes the minute regions (not theregion of the finger) to be included in the image binarized by thebinarizing unit 401. The image (the region having a large pixel valuedifferent from that of the finger) caused by the noise and thebackground exists in the images acquired by the image acquiring unit 101in some cases. The binarizing unit 401 resultantly extracts, as theregion of the finger, such a region as well. Thereupon, theminute-region removing unit 402 obtains respective areas of a pluralityof the regions existing in the binarized image. The minute-regionremoving unit 402 selects the region having a maximum area from amongthem, and extracts the region having a maximum area as the region of thefinger. The reason why the region having a maximum area is extracted asthe region of the finger is that it can be estimated that the regionhaving a maximum area existing in the image is the region of the fingerbecause the region of the finger occupies the majority of the area ofthe image captured by the image acquiring unit 101. In such a manner,the minute-region removing unit 402 can extract the region of the fingerfrom the regions obtained by the binarizing unit 401.

The centerline extracting unit 403 extracts the centerline of the fingeras the reference line from the regions of the finger extracted by theminute-region removing unit 402.

With regard to the finger existing in the image, the axis along adirection from the root of the finger toward the finger tip is definedas a longitudinal axis, and the axis orthogonal to this longitudinalaxis is defined as a lateral axis. Herein, the coordinates of the centerpoints are extracted for each partial image in the lateral direction onthe assumption that centerline to be extracted by the centerlineextracting unit 403 is along the longitudinal axis. Herein, the centerpoint is centrally positioned from a boundary (contour). For example, inthe case that, with the partial image having a width of a one-pixelportion defined as one line, the center point is extracted one line byone line, the processing is performed as follow (see FIG. 5). Thecenterline extracting unit 403 scans one line of the edge of the imagein the lateral direction (in FIG. 5, the vertical direction), andinvestigates the coordinates of both edge points of the region of thefinger within the line. The centerline extracting unit 403 defines thecentral coordinate of the acquired coordinates of both edge points asthe center point of the finger in this line. The centerline extractingunit 403 sequentially updates the line along the longitudinal direction(in FIG. 5, the horizontal direction), and investigates the centerpoints of the fingers in all of the lines. It extracts the centerline ofthe region of the finger in such a manner.

When the center point of the region of the finger is extracted for everyplural lines with the partial image defined as the image of a pluralityof the lines, the center point is extracted, for example, with thefollowing processing. The centerline extracting unit 403, similarly tothe method of extracting the center point one line by one line, extractsthe center point for each line within the plural lines. And, thecenterline extracting unit 403 defines an averaged value of thecoordinates of the center points extracted for each one line within aplurality of the lines as the center point within plural lines. Thecenterline extracting unit 403 extracts the center point of the regionof the finger for every plural lines by sequentially updating the plurallines along the longitudinal direction, and extracting respective centerpoints.

The image correcting unit 103 performs the position correction for theimage of the imaging target acquired by the image acquiring unit 101 byusing the reference line extracted by the reference line extracting unit102. By the way, the reference line extracted by the reference lineextracting unit 102 is inclined or crooked in some cases. The reason isthat the imaging target (finger) is inclined or crooked in some caseswhen the image is acquired by the image acquiring unit 101.

Thereupon, the image correcting unit 103 translates the image for eachpartial image in the lateral direction so that the centerline acquiredby the reference line extracting unit 102 becomes a pre-decided line,for example, a straight line that is horizontal with respect to the leftdirection and the right direction (see FIG. 6). The image correctingunit 103 outputs the image moved in such a manner as theafter-correction image. Additionally, FIG. 6( a) is a view illustratingthe before-correction finger region and its centerline. FIG. 6( b) is aview illustrating the after-correction finger region and its centerline.

And, performing the image correction for each partial image makes itpossible to curtail the arithmetic amount all the more as compared withthe case of applying the rotation processing for the image. Thus, thefast image correction can be realized.

It is also possible to correct the crooked image (see FIG. 7). Forexample, the finger has a joint. The image is easily crooked because thefinger is bent at this joint. The image of the crooked finger is shownin FIG. 7( a). In the rotation processing of the image, the crookedimage is rotated without a modification to the shape. Thus, it isimpossible to correct the crookedness by the rotation processing. Forthis, when one, out of the images acquired from the identical livingbody, is crooked at the moment of collating the images, a collationresult declines. On the other hand, the present invention is capable ofcorrecting the crooked image because each partial image is correctedbased upon the reference line (see FIGS. 7( b) and (c)). FIG. 7( b)shows the before-correction finger region and its centerline. FIG. 7( c)shows the after-correction finger region and its centerline.

The image collating unit 104 performs the collation by using theafter-correction image outputted by the image correcting unit 103.

Next, the details of the image collating unit 104 will be explained.

A block diagram of the image collating unit (device) 104 is shown (seeFIG. 8).

The image collating unit 104 includes a feature extracting unit 801, alinear transforming unit 802, a parameter storing unit 803, and asimilarity calculating unit 804. The feature extracting unit 801 is adevice for extracting the features to be used for the collation fromimage corrected by the image correcting unit 103. The lineartransforming unit 802 is a device for performing a linear transform forthe features extracted by the feature extracting unit 801. The parameterstoring unit 803 is a device having parameters to be used for the lineartransforming unit 802 stored therein. The similarity calculating unit804 is a device for calculating a similarity by using the value acquiredby linear transforming unit 802.

The feature extracting unit 801 extracts the features. With the casethat the imaging target is the finger, the feature is one-dimensionalFourier amplitude spectra in the lateral direction of a surface patternof the finger (or a pattern of the blood vessel of the finger such asthe finger vein) that is typified by the fingerprint. At first, thefeature extracting unit 801 calculates the Fourier amplitude spectra tobe acquired by a one-dimensional discrete Fourier transform line by linewith regard to the lateral direction of after-correction image.Thereafter, the feature extracting unit 801 removes componentsunnecessary for the determination such as direct components, andsymmetric components of the Fourier amplitude spectra, taking intoconsideration the fact that the Fourier amplitude spectra are symmetric,and extracts the features valid for determination.

The linear transforming unit 802 extracts a main component of thefeatures acquired by the feature extracting unit 801. The main componentis extracted by using basis matrix stored in the parameter storing unit803, and performing a linear transform for the features extracted by thefeature extracting unit 801. The basis matrixes stored in the parameterstoring unit 803 are ones obtained in advance by performing the maincomponent analysis for the specially prepared learning set. The maincomponent analysis is one of the techniques of realizing dimensionalreduction of data while minimizing the information loss amount.

The similarity calculating unit 804 performs a matching, which takesposition drift and distortion as to one direction into consideration,for the features of the main component acquired by the lineartransforming unit 802 by using a DP matching method (dynamic programmingmatching method). In the DP matching method, the distance of the DPmatching at the time that a distance between two features becomesminimized is calculated as a similarity between two features. Thesimilarity is acquired as the distance of the DP matching, whereby thesmaller the acquired value, higher the similarity. The above-mentionedtechnique is called a frequency DP matching method.

Next, the second exemplary embodiment obtained by altering theabove-mentioned first embodiment will be explained.

In this exemplary embodiment, the imaging target is the palm. The secondexemplary embodiment differs from the first exemplary embodiment in thispoint. And, the image acquiring unit (device) of this exemplaryembodiment includes a palm guide for efficiently capturing the image ofthe palm in addition to a configuration of the first exemplaryembodiment.

Similarly to the finger in which the fingerprint and the finger veinexist, there exist a palm print and a palm vein in the palm. Similarlyto the fingerprint, the palm print as well has the ridge and the recess.And, in the acquired image, the ridge is bright because the reflectionof light is much, and the recess is dark because the absorption of lightis much.

The above-mentioned palm guide is shown in FIG. 9.

The palm guide includes an imaging scope guide 901 and a second fingerguide 902.

The finger is arranged to the second finger guide 902 at the moment ofcapturing the image of the palm. And, the hand is opened, the thumb andthe little finger are placed in both sides of the imaging scope guide901, the forefinger and the ring finger are placed in a side identicalto that of the second finger (see FIG. 9). Capturing the image of thepalm arranged in such a manner allows a scope beyond the wrist to beacquired as the image. Using the palm guide as mentioned above makes itpossible to roughly decide the position of the palm within the acquiredimage.

Hereinafter, the axis along a direction from the wrist toward the secondfinger is defined as a longitudinal axis of the palm, and the axisorthogonal to this longitudinal axis is defined as a lateral axis of thepalm.

Next, an operation for extracting the reference line from the image ofthe palm acquired by the image acquiring unit (device) will beexplained.

The reference line extracting unit of the palm has a configurationsimilar to that of the reference line extracting unit used for thefinger (see FIG. 4).

The binarizing unit 401 binarizes the image by the threshold processinghaving the pixel value of the acquired image as a reference. This allowsthe region of the palm to be extracted.

The minute-region removing unit 402 removes the minute regions (theregion different from the region of the palm) included in the imagebinarized by the binarizing unit 401.

The centerline extracting unit 403 extracts the reference line from theregion of the palm extracted by the minute-region removing unit 402.With the palm, it is difficult to extract the centerline with a methodsimilar to that of the finger because of an influence of the thumb orthe like. Thereupon, it is favorable to use, for example, the lineobtained by extending the centerline of the second finger as thereference line of the palm. The reason is that the second finger, out ofthe five fingers, has a relatively straight-line shape, and the extendedline of the centerline of the second finger almost coincides with thecenterline in the lateral direction of the palm.

Next, an example of extracting the reference line of the palm is shownin FIG. 10. FIG. 10( a) shows the image of the palm. FIG. 10( b) showsthe image in which the minute regions have been removed. FIG. 10( c)shows the image in which the centerline of the second finger has beenextracted. FIG. 10( d) shows the image in which the centerline of thepalm has been extracted.

The processing of the binarizing unit 401 and the minute-region removingunit 402 are applied (see FIG. 10( b) for the image acquired by theimage acquiring unit 101 (see FIG. 10( a)). As mentioned above, withregard to the image of the palm acquired by the image acquiring unit101, the position of the second finger thereof is roughly is decided bythe palm guide 901 of the image acquiring unit 101. Thereupon, theregion of the second finger is decided from among the image in which theminute regions have been removed at a fixed position. And, theprocessing of the centerline extracting unit 403 is applied for thesecond finger. This allows the centerline of the second finger to beextracted (see FIG. 10( c)). The centerline of the second fingerextracted by the centerline extracting unit 403 is extended, and theextended line is defined as the centerline of the palm (see FIG. 10(d)).

The image correcting unit 103 performs the image correction for theimage of the palm acquired by the image acquiring unit 101 by using thereference line extracted by the reference line extracting unit 102.

The extracted reference line of the palm is inclined due to the rotationand position drift of the hand and the like in some cases. Thereupon,the image is translated for each partial image in the lateral directionwith the processing similar to that of the finger so that the extractedcenterline becomes, for example, a straight line.

The image collating unit 104 performs the image collation by using theafter-correction image acquired by the image correcting unit 103. Theforegoing frequency DP matching method is applied for the palm print andthe palm vein similarly to the case of applying for the fingerprint andthe finger vein, and a collation result is outputted. In such a manner,the collation result is acquired likewise also when the palm is used asthe living body.

Next, the third exemplary embodiment obtained by altering theabove-mentioned first embodiment will be explained. Additionally, thechanging point from the first exemplary embodiment is a point of usingan image acquiring device of a line censor type (see FIG. 11).

The image acquiring unit (device) in this exemplary embodiment includesnear-infrared LEDs 1101, an infrared transparent filter 1102, and animaging device 1103 (see FIG. 11).

The near-infrared LED 1101 and the infrared transparent filter 1102 areidentical to the near-infrared LED 201 and the infrared transparentfilter 202 of the foregoing first exemplary embodiment, respectively.

The imaging device 1103 includes a one-dimensional line censor (or astrip-shaped two-dimensional line censor) and a lenticular lens.Assuming such a structure makes it possible to capture the image of onepart of the finger in a line shape as the one-dimensional partial image(or the partial image having a rectangular region). And, the capturedpartial images are jointed together, thereby allowing the image of anentirety of the finger to be synthesized. The image synthesized in sucha manner can be used similarly to the case of the image captured by theimage acquiring unit in the foregoing first exemplary embodiment.

A reference line extracting unit, an image correcting unit, and an imagecollating unit of this exemplary embodiment are identical to onesexplained in the foregoing first exemplary embodiment. Additionally, thereference line extracting unit and the image correcting unit of thethird exemplary embodiment may be configured as follows. This imageacquiring unit acquires the one-dimensional or two-dimensional imagehaving a rectangular region to the scanning of the finger because ofusing the image acquiring device of a line sensor type. Thereupon, thereference line extracting unit of the third exemplary embodimentperforms the reference line extraction and the image correction wheneverit acquires the image having a rectangular region image by scanning thefinger. That is, the reference line extracting unit outputs theafter-correction image as follows. At first, the finger is scanned bythe image acquiring unit, and the one-dimensional or two-dimensionalimage with a rectangular region is acquired. The processing of thereference line extracting unit is applied for the acquired image with arectangular region similarly to the case of the partial image in thelateral direction in the foregoing first embodiment. This allows thecenterline to be acquired. And, for example, the image correction ofarranging the acquired centerline in the central part of the image isperformed so as to yield the pre-decided arrangement. This processing isrepeated until the entirety of the finger is scanned. And, by jointingthe images corrected for each scan together, the after-correction imageis outputted.

As mentioned above, activating the image acquiring unit, the referenceline extracting unit, and the image collating unit makes it possible tosequentially performing the image correction after acquiring the imageby the scanning of the finger. And, the after-correction image isoutputted when the scanning of the finger is finished. This shortens thetime ranging from the finishing of the image acquisition to acquisitionof the final collation result similarly to the case of the foregoingfirst exemplary embodiment as compared with the case of performing theimage correction after the acquisition of the image. That is, the waittime ranging from the finishing of the manipulation up to acquisition ofthe collation result is shortened. As a result, quicker response can begained, and usability is enhanced.

Next, the fourth exemplary embodiment obtained by altering theabove-mentioned first embodiment will be explained. Additionally, thechanging point from the first exemplary embodiment is a point that acenterline correcting unit is added to the reference line extractingunit.

The reference line extracting unit (device) of the fourth exemplaryembodiment is shown in FIG. 12. According to FIG. 12, the reference lineextracting unit (device) of the fourth exemplary embodiment includes abinarizing unit 1201, a minute-region removing unit 1202, a centerlineextracting unit 1203, and a centerline correcting unit 1204.

The binarizing unit 1201, the minute-region removing unit 1202, and thecenterline extracting unit 1203 are similar to that of the foregoingfirst exemplary embodiment.

The centerline correcting unit 1204 corrects the centerline of theimaging target extracted by the centerline extracting unit 1203 asfollows.

The minute-region removing unit 1202 removes the regions other than theregion having a maximum area similarly to the case of the foregoingfirst exemplary embodiment.

However, the region estimated to be the imaging target and thebackground, which remains as the region, are contact with each other inthe binarized image in some cases (see FIG. 13( a)). In such a case, aninfluence of the background is not eliminated although the minuteregions are removed with the area defined as a reference. Thus, thecenterline is unnaturally crooked in the portion influenced by thebackground although the centerline extracting unit extracts thecenterline (see FIG. 13( a)). Thereupon, the centerline needs to becorrected. For example, the technique of defining the line equivalent tothe maximum length as the centerline when two centerlines or more existis thinkable. Or, the technique of calculating the centerline from adispersion of the center points is also thinkable.

By the way, originally, the centerline of the finger correctly extractedis an approximately straight line (or a quietly curved line). Thus, forthe centerline of the finger obtained by the centerline extracting unit1203, the centerline correcting unit 1204 performs the processing ofchanging the coordinate of the center point acquired for a certainpartial image to an average value of the coordinates of the centerpoints within a certain scope, which extends ahead of and behind theabove center point. For example, the scope for obtaining the averagedvalue of the coordinates of the center points is defined as a scopeequivalent to 10% of the length in the longitudinal direction of theimage, and the averaged value of the coordinates is obtained for eachabove scope. Performing such a change allows the unnaturally crookedportion caused by an influence of the background to be become shaped soas to conform to the tendency of the centerline of the surroundings (seeFIG. 13( b)). That is, correcting the centerline as mentioned aboveallows an influence of the background not eliminated by theminute-region removing unit 1202 as well to be alleviated. That is, itbecomes possible to extract the more correct centerline of the finger.

The centerline can be corrected with the method as shown in FIG. 14 inaddition to the above-mentioned methods. FIG. 14( a) shows thebefore-correction centerline. FIG. 14( b) shows the before-correctionaveraged value of the coordinates of the center points. In FIG. 14( c),the center points exceeding a threshold have been removed. FIG. 14( d)shows the after-correction centerline.

That is, for the centerline of the finger acquired by the centerlineextracting unit 1203, an averaged value of the coordinates of the centerpoints within a certain scope, which extends ahead of and behind acertain center point, is obtained (see FIG. 14( b)). And, the centerpoints exceeding a threshold are removed from the centerline bycomparing the centerline of the finger acquired by the centerlineextracting unit 1203 with the obtained averaged value of the coordinates(see FIG. 14( c)). Thereafter, the coordinate of the removed centerpoint is defined as an average value of the coordinates of the remainingcenter points, and the after-correction centerline is acquired (see FIG.14( d)). The coordinates of the center points of the portion unnaturallycrooked due to an influence of the background can be removed also withsuch a method. That is, it becomes possible to alleviate an influence ofthe background.

And, correcting the centerline as mentioned above makes it possible toacquire more accurate image as compared with the case of the foregoingfirst exemplary embodiment. And, a precision of the image collation isenhanced.

While the technique of extracting the centerline as the reference linewas used in the above-mentioned exemplary embodiments, the technique aswell of extracting the contour line instead of the centerline can beadopted likewise.

Also when the contour line is used as the reference line, the partialimage having a width of a one-pixel portion is defined as one linesimilarly to the case of using the centerline. One line of the edge ofthe image is scanned in the lateral direction (in FIG. 5, the verticaldirection), and the coordinates of both edge points of the region of thefinger within the line are investigated. The acquired coordinates ofboth edge points are defined as contour points of the finger in thisline. The lines are sequentially updated along the longitudinaldirection (in FIG. 5, the horizontal direction), and the contour pointsof the finger in all of the lines are investigated. In such a manner,the contour points of the region of the finger are extracted.Additionally, the partial image may be defined as the image of plurallines to extract the contour points of the region of the finger forevery plural lines similarly to the case of using the centerline.

The image subjected to the movement like the exemplary embodimentsmentioned above with at least one part of the contour line acquired asmentioned above defined as the reference line is outputted as theafter-correction image.

FIG. 15 is a block diagram of the collating device in accordance withthe present invention.

This collating device includes a reference line extracting unit 102, animage correcting unit 103, and an image collating unit 104. Thereference line extracting unit 102 is a device for extracting apredetermined reference line in the image. The image correcting unit 103is a device for correcting the image by moving (translating) it for eachpartial image so that the reference line acquired by the reference lineextracting unit 102 becomes a pre-determine one. The image collatingunit 104 is a device for collating the image corrected by the imagecorrecting unit 103 with a predetermined image (already registeredimage). This collating device is a device in which the image acquiringunit of the collating unit of FIG. 1 is omitted. Thus, afunction/operation of this collating device or the like can be graspedfrom the above-mentioned explanation, so detailed explanation isomitted.

FIG. 16 is a block diagram of the correcting device in accordance withthe present invention.

This correcting device includes a reference line extracting unit 102 andan image correcting unit 103. The reference line extracting unit 102 isa device for extracting a predetermined reference line in the image. Theimage correcting unit 103 is a device for correcting the image by moving(translating) it for each partial image so that the reference lineacquired by the reference line extracting unit 102 becomes apre-determine one. That is, this correcting device is a device in whichthe image acquiring unit and the image collating device of the collatingunit of FIG. 1 are omitted. Thus, a function/operation of thiscorrecting device or the like can be grasped from the above-mentionedexplanation, so detailed explanation is omitted.

FIG. 17 is a block diagram of the information processing system havingthe collating device of the present invention implemented therein.

The information processing system shown in FIG. 17 includes a processor100, a program memory 101, a storing unit 12, and an image acquiringunit 11.

The program memory 101 has a program filed therein for causing theprocessor 100 to execute the above-mentioned reference line extractingprocessing, image correcting processing, and image collating processing.And, the processor 100 operates under this program.

And, the present invention is realized with the above-mentioned computerprogram.

Additionally, there is no necessity for performing all of the referenceline extracting processing, the image correcting processing, and theimage collating processing with the program. For example, one partthereof may be configured with hardware.

Above, although the present invention has been particularly describedwith reference to the preferred embodiments, it should be readilyapparent to those of ordinary skill in the art that the presentinvention is not always limited to the above-mentioned embodiment, andchanges and modifications in the form and details may be made withoutdeparting from the spirit and scope of the invention.

This application is based upon and claims the benefit of priority fromJapanese patent application No. 2008-263483, filed on Oct. 10, 2008, thedisclosure of which is incorporated herein in its entirety by reference.

INDUSTRIAL APPLICABILITY

The present invention may be applied to an application of the personalauthentication system. The present invention may be applied, forexample, to applications such as a log-in system to personal computersand a utilization control system of mobile telephones besides a gatepassing control system and an immigration control system. That is, thepresent invention may be applied for an authentication system at themoment of performing a border control for space and object necessitatingsecurity. Further, the present invention may be applied for a system formanaging individuals as well, for example, a time/attendance managementsystem.

REFERENCE SIGNS LIST

101 image acquiring unit

102 reference line extracting unit

103 image correcting unit

104 image collating unit

201 near-infrared LED

202 infrared transparent filter

203 imaging device

301 step 301

302 step 302

303 step 303

304 step 304

305 step 305

306 step 306

307 step 307

401 binarizing unit

402 minute-region removing unit

403 centerline extracting unit

501 one line in a lateral direction

502 finger region

503 center point

601 before-correction centerline

602 before-correction finger region

603 after-correction centerline

604 after-correction finger region

701 crooked finger

702 extracted finger region

703 extracted centerline of a finger region

704 after-correction finger region

705 after-correction centerline

801 feature extracting unit

802 linear transforming unit

803 parameter storing unit

804 similarity calculating unit

901 imaging scope guide

902 second finger guide

1001 region of a palm

1002 centerline of a second finger

1003 centerline of a palm

1101 near-infrared LED

1102 infrared transparent filter

1103 imaging device

1201 binarizing unit

1202 minute-region removing unit

1203 centerline extracting unit

1204 centerline correcting unit

1301 before-correction centerline

1302 before-correction finger region

1303 after-correction centerline

1304 after-correction finger region

1401 before-correction centerline

1402 center point influenced by a background

1403 averaged value of coordinates of center points

1404 centerline in which center points exceeding a threshold have beenremoved

1405 after-correction centerline

1501 after-extraction contour

1502 contour subjected to rotation correction

1. A collating device for collating an image; comprising: a referenceline extracting unit for extracting a predetermined reference line inthe image; an image correcting unit for correcting the image by movingit for each partial image so that the reference line acquired by saidreference line extracting unit becomes a pre-decided one; and an imagecollating unit for collating the image corrected by said imagecorrecting unit with a predetermined image.
 2. A collating deviceaccording to claim 1, wherein said reference line extracting unit is adevice for extracting a centerline or a contour line of the image.
 3. Acollating device according to claim 1, wherein said reference lineextracting unit comprises: a binarizing unit for extracting one regionor plural regions by binarizing the image; a minute-region removing unitfor extracting the region having a maximum area in the region extractedby said binarizing unit; and a centerline extracting unit for extractingthe centerline from the region extracted by said minute-region removingunit.
 4. A collating device according to claim 1, wherein said referenceline extracting unit comprises: a binarizing unit for extracting oneregion or plural regions by binarizing the image; a minute-regionremoving unit for extracting the region having a maximum area in theregion extracted by said binarizing unit; and a contour line extractingunit for extracting the contour line from the region extracted by saidminute-region removing unit.
 5. A collating device according to claim 3,wherein said reference line extracting unit further comprises acenterline correcting unit for correcting the centerline on the basis ofthe line equivalent to a maximum length when the centerline extracted bysaid centerline extracting unit is comprised of two lines or more.
 6. Acollating device according to claim 3, wherein said reference lineextracting unit further comprises a centerline correcting unit for, whenan averaged value of coordinates of center points within a certainscope, which extends ahead of and behind a certain center point, exceedsa threshold, correcting a centerline by removing the above center pointand changing the coordinate of the removed center point to an averagevalue of the coordinates of the remaining center points, said centerlineextracted by said centerline extracting unit.
 7. A collating deviceaccording to claim 4, wherein said reference line extracting unitfurther comprises a contour line correcting unit for correcting thecontour line on the basis of the line equivalent to a maximum lengthwhen the contour line extracted by said contour line extracting unit iscomprised of two lines or more.
 8. A collating device according to claim4, wherein said reference line extracting unit further comprises acontour line correcting unit for, when an averaged value of coordinatesof the contour points within a certain scope, which extends ahead of andbehind a certain contour point, exceeds a threshold, correcting acontour line by removing the above contour point and changing thecoordinate of the removed contour point to an average value of thecoordinates of the remaining contour points, said contour line extractedby said contour line extracting unit.
 9. A collating device according toclaim 1, wherein said image correcting unit is a device for correctingthe image by translating it for each partial image so that the referenceline acquired by said reference line extracting unit becomes apre-decided one.
 10. A collating device according to claim 1, saidcollating device being a collating device for collating the image of afinger.
 11. A collating device according to claim 1, said collatingdevice being a collating device for collating the image of a palm.
 12. Acollating device according to claim 1, wherein said image collating unitcomprises: a device for performing a Fourier transform line by line; adevice for extracting a main component of features by each partial imageby performing a linear transform for Fourier amplitude spectra obtainedby said Fourier transform; and a device for computing a similarity witha dynamic programming matching operation by using said main component offeatures obtained by said linear transform.
 13. A collating deviceaccording to claim 12 wherein said device for extracting the maincomponent of features by each partial image comprises: a storing devicehaving basis matrixes stored therein that have been obtained byperforming a main component analysis for a learning image set; and adevice for obtaining the main component by performing a linear transformfor the image by using said stored basis matrixes.
 14. A collatingdevice according to claim 1, further comprising an image acquiring unitfor acquiring the image.
 15. A collating method of collating an image;comprising: a reference line extracting step of extracting apredetermined reference line in the image; an image correcting step ofcorrecting the image by moving it for each partial image so that thereference line acquired by said reference line extracting step becomes apre-decided one; and a collating step of collating the image correctedby said image correcting step with a predetermined image.
 16. Acollating method according to claim 15, wherein said reference lineextracting step is a step of extracting a centerline or a contour lineof the image.
 17. A collating method according to claim 15, wherein saidreference line extracting step comprises: a binarizing step ofextracting one region or plural regions by binarizing the image; aminute-region removing step of extracting the region having a maximumarea from the region extracted by said binarizing step; and a centerlineextracting step of extracting the centerline from the region extractedby said minute-region removing step.
 18. A collating method according toclaim 15, wherein said reference line extracting step comprises: abinarizing step of extracting one region or plural regions by binarizingthe image; a minute-region removing step of extracting the region havinga maximum area in the region extracted by said binarizing step; and acontour line extracting step of extracting the contour line from theregion extracted by said minute-region removing step.
 19. A collatingmethod according to claim 17, wherein said reference line extractingstep further comprises a centerline correcting step of correcting thecenterline on the basis of the line equivalent to a maximum length whenthe centerline extracted by said centerline extracting step is comprisedof two lines or more.
 20. A collating method according to claim 17,wherein said reference line extracting step further comprises acenterline correcting step of, when an averaged value of coordinates ofcenter points within a certain scope, which extends ahead of and behinda certain center point, exceeds a threshold, correcting a centerline byremoving the above center point and changing the coordinate of theremoved center point to an average value of the coordinates of theremaining center points, said centerline extracted by said centerlineextracting step.
 21. A collating method according to claim 18, whereinsaid reference line extracting step further comprises a contour linecorrecting step of correcting the contour line on the basis of the lineequivalent to a maximum length when the contour line extracted by saidcontour line extracting step is comprised of two lines or more.
 22. Acollating method according to claim 18, wherein said reference lineextracting step further comprises a contour line correcting step of,when an averaged value of coordinates of the contour points within acertain scope, which extends ahead of and behind a certain contourpoint, exceeds a threshold, correcting a contour line by removing theabove contour point and changing the coordinate of the removed contourpoint to an average value of the coordinates of the remaining contourpoints, said contour line extracted by said contour line extractingstep.
 23. A collating method according to claim 15, wherein said imagecorrecting step is a step of correcting the image by translating it foreach partial image so that the reference line acquired by said referenceline extracting step becomes a pre-decided one.
 24. A collating methodaccording to claim 15, said collating method being a collating method ofcollating the image of a finger.
 25. A collating method according toclaim 15, said collating method being a collating method of collatingthe image of a palm.
 26. A collating method according to claim 15,wherein said collating step comprises: a step of for performing aFourier transform line by line; a step of for extracting a maincomponent of features by each partial image by performing a lineartransform for Fourier amplitude spectra obtained by said Fouriertransform; and a step of computing a similarity with a dynamicprogramming matching operation by using said main component of featuresobtained by said linear transform.
 27. A collating method according toclaim 26, wherein said step of extracting the main component of featuresby each partial image comprises a step of obtaining the main componentby performing a linear transform for the image by using basis matrixesobtained by performing a main component analysis for a learning imageset.
 28. A program for causing a collating device to execute: areference line extracting process of extracting a predeterminedreference line in an image; an image correcting process of correctingthe image by moving it each partial image so that the reference lineacquired by said reference line extracting process becomes a pre-decidedone; and a collating process of collating the image corrected by saidimage correcting process with a predetermined image.
 29. A programaccording to claim 28, wherein said reference line extracting process isa process of extracting a centerline or a contour line of the image. 30.A program according to claim 28, wherein said reference line extractingprocess comprises: a binarizing process of extracting one region orplural regions by binarizing the image; a minute-region removing processof extracting the region having a maximum area in the region extractedby said binarizing process; and a centerline extracting process ofextracting the centerline from the region extracted by saidminute-region removing process.
 31. A program according to claim 28,wherein said reference line extracting process comprises: a binarizingprocess of extracting one region or plural regions by binarizing theimage; a minute-region removing process of extracting the region havinga maximum area in the region extracted by said binarizing process; and acontour line extracting process of extracting the contour line from theregion extracted by said minute-region removing process.
 32. A programaccording to claim 30, wherein said reference line extracting processcomprises a centerline correcting process of correcting the centerlineon the basis of the line equivalent to a maximum length when thecenterline extracted by said centerline extracting process is comprisedof two lines or more.
 33. A program according to claim 30, wherein saidreference line extracting process comprises a centerline correctingprocess of, when an averaged value of coordinates of center pointswithin a certain scope, which extends ahead of and behind a certaincenter point, exceeds a threshold, correcting a centerline by removingthe above center point and changing the coordinate of the removed centerpoint to an average value of the coordinates of the remaining centerpoints, said centerline extracted by said centerline extracting process.34. A program according to claim 31, wherein said reference lineextracting process comprises a contour line correcting process ofcorrecting a contour line by changing the coordinate of a contour pointto an average value of the coordinates of the contour points within acertain scope, which extends ahead of and behind the above contourpoint, said contour line extracted by said contour line extractingprocess.
 35. A program according to claim 31, wherein said referenceline extracting process comprises a contour line correcting process of,when an averaged value of coordinates of contour points within a certainscope, which extends ahead of and behind a certain contour point,exceeds a threshold, correcting a contour line by removing the abovecontour point and changing the coordinate of the removed contour pointto an average value of the coordinates of the remaining contour points,said contour line extracted by said contour line extracting process. 36.A program according to claim 28, wherein said image correcting processis a process of correcting the image by translating it for each partialimage so that the reference line acquired by said reference lineextracting process becomes a pre-decided one.
 37. A program according toclaim 28, said program being a process of collating the image of afinger.
 38. A program according to claim 28, said program being aprocess of collating the image of a palm.
 39. A program according toclaim 28, wherein said collating process comprises: a process of forperforming a Fourier transform line by line; a process of extracting amain component of features by each partial image by performing a lineartransform for Fourier amplitude spectra obtained by said Fouriertransform; and a process of computing a similarity with a dynamicprogramming matching operation by using said main component of featuresobtained by said linear transform.
 40. A program according to claim 39,wherein said process of extracting the main component of features byeach partial image comprises a process of obtaining the main componentby performing a linear transform for the image by using basis matrixesobtained by performing a main component analysis for a learning imageset.
 41. A correcting device, comprising: a reference line extractingunit for extracting a predetermined reference line in an image; and animage correcting unit for correcting the image by moving it for eachpartial image so that the reference line acquired by said reference lineextracting unit becomes a pre-decided one.
 42. A correcting method,comprising: a reference line extracting step of extracting apredetermined reference line in an image; and an image correcting stepof correcting the image by moving it for each partial image so that thereference line acquired by said reference line extracting step becomes apre-decided one.
 43. A program for causing a correcting device toexecute: a reference line extracting process of extracting apredetermined reference line in an image; and an image correctingprocess of correcting the image by moving it for each partial image sothat the reference line acquired by said reference line extractingprocess becomes a pre-decided one.